Machine tool device and its working fluid feed device

ABSTRACT

The present invention relates to a machine tool system and a machining liquid supply device for machining a workpiece by a tool such as a grinding wheel or a milling cutter, and solves the problem of how to supply the machining liquid optimally to an area where the tool engages with the workpiece. In order to solve this problem, the present invention is so configured that during the machining of a workpiece with a tool (T) detachably mounted on a spindle ( 12 ) of a machine tool (MT), the machining liquid supply device ( 18 ) for supplying a machining liquid to a machining area of the tool (T) is provided with an opening end at the forward end of a machining liquid supply nozzle ( 20 ), and can give the movements in a radial direction and a circumferential direction through 360° with respect to the axis of the spindle ( 12 ) about the spindle head ( 12 ) having the spindle ( 12 ) through a rotational supporting body ( 16 ) by means of linear movement means ( 80 ) and rotating movement means ( 30 ), respectively.

TECHNICAL FIELD

The present invention relates to a machine tool system and a machiningliquid supply device thereof. More particularly, the present inventionrelates to a machine tool system and a machining liquid supply devicethereof capable of most properly achieving the removal of chips and thecooling of a workpiece with a machining liquid by always spouting itfrom an optimal position, and in an optimal direction, relative to apart of the workpiece being machined during the machining of theworkpiece with a tool. The present invention also relates to a machinetool system and a machining liquid supply device capable of spouting amachining liquid in an optimal machining liquid supply mode on a part ofa workpiece being machined in accordance with the diameter and machiningcondition of a tool having peripheral working elements, such as agrinding wheel or various milling cutters, and in accordance with thevariation of the positional relation between the tool and the workpiecewhen machining the workpiece with the tool.

BACKGROUND ART

Especially in the case where a metal workpiece is machined by a tool ofa machine tool system, it is essential to supply a machining liquid overthe part of the workpiece being machined in order to ensure asatisfactory cooling action for removing the heat generated in the partof the workpiece being machined and to promote the smooth machiningaction of the tool by removing the chips generated by the machining.

A conventional machining liquid supply device used in a conventionalmachine tool can be, for example, a grinding liquid supply devicedisclosed in Japanese Unexamined Utility Model Publication (Kokai) No.61-124366, which is hereinafter referred to as a first prior art. Thispublication discloses what may be called a manually operated type ofmachining liquid supply device, in which a machining liquid nozzledisposed in alignment with a tangent to a grinding wheel at a grindingpoint is supported on a wheel guard so as to be movable in directionsperpendicular to the same tangent to the grinding wheel, so that themachining liquid can be spouted in a direction tangential to thegrinding wheel at the grinding point by the operator operating an adjusthandle regardless of a change in the diameter of the grinding wheel. Themachining liquid supply device according to the first prior art,however, is not perfectly satisfactory because, when the grinding pointis changed during a process of grinding a workpiece with a grindingwheel, the machining liquid cannot be spouted in a direction tangentialto the grinding wheel at a changed grinding point.

A second prior art is a method of controlling a position of a grindingliquid spouting nozzle which is disclosed in Japanese Unexamined PatentPublication (Kokai) No. 1-146662. More specifically, this patentpublication discloses a method in which a grinding liquid spoutingnozzle is disposed in such a manner as to be capable of being turned forindexing about a spindle holding a grinding wheel during a contourgrinding process with the grinding wheel, and the grinding liquidspouting nozzle is controlled in position to direct it toward a grindingpoint according to a program for controlling the movement of thegrinding wheel during the grinding process. In this conventional methodof spouting the grinding liquid according to the second prior art,however, the spouting direction of the grinding liquid is adjusted byturning the grinding liquid spouting nozzle about the spindle when thegrinding point where the grinding wheel grinds a workpiece is displaced,and therefore the grinding liquid spouting nozzle is not allowed to moveradially with respect to the center of the grinding wheel. Thus, thesecond prior art teaches nothing about a method of correctly adjustingthe grinding liquid spouting direction of the grinding liquid spoutingnozzle when the grinding process is performed with a grinding wheel of adifferent diameter held on the spindle.

A third prior art is a water spouting device for a machining centerdisclosed in Japanese Unexamined Patent Publication (Kokai) No. 6-31582.This water spouting device for a machining center is capable ofversatilely spouting water either in a horizontal direction or verticaldirection through a water spouting nozzle to a machining point where thetool of the machining center cuts a workpiece to allow water to bespouted always toward the machining point. This water spouting device isconfigured such that the water spouting nozzle can be moved about aspindle holding a tool by rotation of a gearing, and when the machiningpoint moves horizontally, the water spouting nozzle can move followingthe moving angle to spout water toward the machining point. When themachining point changes in height, on the other hand, the base portionof the water spouting nozzle is rotated to move the tip thereofvertically, thereby allowing the water spouting nozzle to spout watertoward the machining point.

The water spouting device for a machining center according to the thirdprior art, however, is not configured to be movable radially withrespect to the center of the tool held on the spindle. Therefore, whenthe diameter.of the tool changes, the water spouting direction of thewater spouting nozzle, disadvantageously, cannot be adjusted withrespect to the machining point with sufficient accuracy.

A fourth prior art is a grinding machine provided with a wheel guard fora grinding wheel, disclosed in U.S. Pat. No. 4,619,078. In this knowngrinding machine, this wheel guard covers the grinding wheel held on aspindle and carries a machining liquid supply nozzle, which isconfigured to be turnable about the spindle together with the wheelguard and to be movable radially with respect to the spindle inaccordance with the diameter of the grinding wheel, thereby supplyingthe machining liquid to the contact point between the grinding wheel andthe workpiece. Specifically, the machining liquid supply nozzle isturned together with the wheel guard so that the wheel guard and theworkpiece do not interfere with each other and, in response to reduceddiameter of the grinding wheel due to wearing, the nozzle is adjustedwith respect to the wheel guard by driving a motor, thereby to adjustthe direction in which the machining liquid is supplied, or to move thewheel guard in a radial direction of the grinding wheel.

The fourth prior art, however, is a special machine tool, such as asurface grinder, and the wheel guard for covering the grinding wheel isan essential component. As a result, an attempt to mount a tooldetachably on the spindle by an automatic tool changer such as in amachining center leads to the problem that the automatic tool changingoperation cannot be achieved because the wheel guard interferes with thetool changing operation of the automatic tool changer. The disadvantageof this prior art, therefore, is the lack of versatility ofapplicability to the machining portions of various machine tools otherthan the surface grinder. Furthermore, the known grinding machine doesnot have any axis about which the workpiece is rotated, and can feed theworkpiece only linearly along three axes, i.e., X-, Y- and Z-axes.Consequently, it has the problem that some workpieces of a particularshape interfere unavoidably with the wheel guard, or that the machiningliquid cannot be properly supplied to the machining area if theinterference between the workpiece and the wheel guard is avoided. Also,there is no specific disclosure of a structure or an arrangement forrotating or radially moving the wheel guard, or the machining liquidsupply nozzle associated with it, in response to the driving force fromthe motor. Therefore, the utility of this prior art is insufficient inview of practical use.

In addition, the fourth prior art is not provided with any toolmeasuring means for measuring the diameter of the grinding wheel andnothing is disclosed with regard to techniques of automaticallyadjusting the radial position of the machining liquid supply nozzlerelative to the grinding wheel on the basis of an acquired measurementof the tool diameter of the grinding wheel when the grinding wheel isabraded or the diameter thereof is changed by dressing or truing.Further, an attempt to adjust the circumferential position of themachining liquid supply nozzle about the grinding wheel encounters theproblem that the positioning over the entire circumference of thegrinding wheel is hampered by the wheel guard.

DISCLOSURE OF THE INVENTION

Accordingly, a principal object of the present a invention is to providea machine tool system and its machining liquid supply device capable ofpositioning a machining liquid nozzle included in the machining liquidsupply device at an optimal position relative to an engaging area wherea tool engages with a workpiece from the viewpoint of chip removal andcooling in accordance with a change in the diameter of a tool detachablymounted on a spindle or a change in a machining point of various machinetools not limited to a specific type of machine tool, while at the sametime supplying the machine liquid into the engaging area.

Another object of the present invention is to provide a machine toolsystem and its machining liquid supply device capable of positioning amachining liquid nozzle of the machining liquid supply device at theoptimal machining liquid supply position relative to an area where atool engages with a workpiece, by moving the machining liquid supplydevice to a desired machining liquid supply position by means of arotary mechanism free of a dead angle about a spindle of the machinetool system, and further by positioning the machining liquid nozzle atthe optimal machining liquid position in cooperation with a linearmovement mechanism for linearly moving the machining liquid nozzle in aradial direction or a turning movement mechanism for turning themachining liquid nozzle.

Further object of the present invention is to provide a machine toolsystem and its machining liquid supply device capable of starting amachining process, in the case where a tool is reconditioned, afterrepositioning the machining liquid nozzle automatically following abefore-and-after change in a diameter of the reconditioned tool.

Specifically, according to a first aspect of the present invention,there is provided a machine tool system for machining a workpiece bymoving a tool mounted on a spindle and the workpiece mounted on a tableincluded in the machine tool system relative to each other in threedirections along an X-axis, a Y-axis and Z-axis, which comprises:

a spindle head for rotatably supporting the spindle;

a column for movably supporting the spindle head;

a tool mounting means for detachably mounting the tool on the spindle;

a machining liquid supply means including a machining liquid nozzle forspouting a machining liquid toward a machining area where the toolengages with the workpiece, and connected by piping to a machiningliquid source;

a cylindrical supporting means disposed in an area surrounding thecircumference of the spindle for movably supporting the machining liquidnozzle of the machining liquid supply means;

a radial moving means for positioning, in a radial direction of thetool, the machining liquid nozzle of the machining liquid supply meanssupported on the cylindrical supporting means, by linearly moving orturning the machining liquid nozzle with respect to the tool; and

a circumferential moving means for positioning the machining liquidnozzle of the machining liquid supply means over the entirecircumference of the tool by rotating the cylindrical supporting means.

Preferably, the radial moving means comprises a rack located on themachining liquid nozzle of the machining liquid supply means, a pinionmovable relative to the cylindrical supporting means and in mesh withthe rack, a worm wheel movable relative to the cylindrical supportingmeans together with the pinion, a worm in mesh with the worm wheel, anda linear movement motor fixed on the column for driving to rotate theworm.

Preferably, the radial moving means comprises a pinion located on themachining liquid nozzle of the machining liquid supply means, a wormwheel having a pinion in mesh with the pinion and being movable relativeto the cylindrical supporting means, a worm in mesh with the worm wheel,and a turning movement motor fixed on the column for driving to rotatethe worm.

Preferably, the circumferential moving means comprises a worm wheelintegrated with the cylindrical supporting means, a worm in mesh withthe worm wheel, and a rotating movement motor fixed on the column fordriving to rotate the worm.

Preferably, the system further comprises a rotary table having at leastone rotational feed shaft and a work rotating means for rotationallyfeeding the workpiece mounted on the rotary table.

In addition, preferably, in the case where the tool mounted on thespindle is a grinding wheel, the machine tool system further comprises atool measuring means located in a part of a structure of the machinetool system for measuring a diameter or a tip position of the grindingwheel mounted on the spindle.

Moreover, preferably, in the case where the tool mounted on the spindleis a grinding wheel, the machine tool system further comprises a toolreconditioning means located on the column for truing or dressing anouter peripheral portion of the grinding wheel mounted on the spindle.

According to a second aspect of the present invention, there is provideda machining liquid supply device of a machine tool system for supplyingthe machining liquid to a machining area where a tool mounted on aspindle engages with a workpiece mounted on a table included in themachine tool system, which comprises:

a machining liquid supply means including a machining liquid nozzle forspouting the machining liquid toward the machining area and connected bypiping to a machining liquid source;

a cylindrical supporting means disposed in an area surrounding thecircumference of the spindle for movably supporting the machining liquidnozzle of the machining liquid supply means;

a radial moving means for positioning, in a radial direction of thetool, the machining liquid nozzle of the machining liquid supply meanssupported on the cylindrical supporting means, by linearly moving orturning the machine liquid nozzle with respect to the tool; and

a circumferential moving means for positioning the machining liquidnozzle of the machining liquid supply means over the entirecircumference of the tool by rotating the cylindrical supporting means.

Preferably, the radial moving means comprises a rack located on themachining liquid nozzle of the machining liquid supply means, a pinionmovable relative to the cylindrical supporting means and in mesh withthe rack, a worm wheel movable relative to the cylindrical supportingmeans together with the pinion, a worm in mesh with the worm wheel, anda linear movement motor fixed on the column for driving to rotate theworm.

Preferably, the radial moving means comprises a pinion located on themachining liquid nozzle of the machining liquid supply means, a wormwheel having a pinion in mesh with the pinion and being movable relativeto the cylindrical supporting means, a worm in mesh with the worm wheel,and a turning movement motor fixed on a part of a structure of themachine tool system for driving to rotate the worm.

Preferably, the circumferential moving means comprises a worm wheelintegrated with the cylindrical supporting means, a worm in mesh withthe worm wheel, and a rotating movement motor fixed on a part of astructure of the machine tool system for driving to rotate the worm.

By provision of the cylindrical supporting means for movably supportingthe machining liquid nozzle of the machining liquid supply means forspouting the machining liquid toward the machining area where the toolengages with the workpiece, on the area surrounding the circumference ofthe spindle supported rotatably on the spindle head, the presentinvention can achieve operations of linearly moving or turning themachining liquid nozzle of the machining liquid supply means in theradial direction of the tool by means of the radial moving means locatedon the cylindrical supporting means, and rotating the machining liquidnozzle of the machining liquid supply means over the entirecircumference about the tool, thereby positioning the machining liquidnozzle so as to spout the machining liquid toward the machining area.

The machine tool system and the machining liquid supply device accordingto the invention having the arrangement and operations as describedabove, in performing the machining process such as grinding or cuttingon the workpiece W by a machining tool T such as a grinding wheel or amilling cutter of the machine tool MT, can supply and spout the machineliquid through the machining liquid supply nozzle of the machiningliquid supply device to the machining area or the contact area P of thetool T from the optimum machining liquid supply position, i.e. from themost proper position for removing the machining chips and cooling boththe tool T and the workpiece W. Further, when setting the opening end ofthe machining liquid supply nozzle in most proper position andorientation for optimal machining liquid supply, the machining liquidsupply device itself can be rotated over the entire circumference aboutthe rotational axis of the spindle. Therefore, the setting of theposition and orientation can be performed without any difficulty inspite of the change in any of the various conditions such as the shapeand the limitation of the installation of the workpiece W.

It should be understood from the foregoing description that the presentinvention is not limited to the grinding machine for performing thegrinding process but is applicable as it is to the other machine toolsystem such as a cutting machine using a milling cutter with equaleffect.

In addition, according to the present invention, even if the diameter ofthe tool in use is changed by the exchange of the tools T such as thegrinding wheel T using the tool changing means or the wear of the toolin use causes the change in the diameter thereof, the tool diameter canbe measured and the setting of the position and orientation of themachining liquid supply nozzle of the machining liquid supply device canbe properly adjusted and moved on basis of the measured tool diameter.In this way, the machining liquid can be always supplied from theoptimal position to the machining area of the tool.

As described above, in view of the fact that the position for supplyingthe machining liquid to the machining area of the tool of the machinetool system can be always set in an optimal condition for coolingfunction and chip removal function, both the machining accuracy and thesurface roughness can be remarkably improved in the machining operationapplied by the tool T to the workpiece W. Further, the machining toolcan be always properly and effectively cooled while at the same timeremoving the chips. This can decrease the wearing of the tool andresults in a reduced machining cost.

Also, this invention is so configured that the setting and thepositioning of the machining liquid supply nozzle of the machiningliquid supply device can be automatically achieved in both radial andcircumferential directions with respect to the axis of the spindle,respectively, by the rotating movement means and linear movement orturning movement means including a driving motor with a servo motor as adriving source. The application of the invention to the automaticmachine tool such as a machining center, therefore, can contribute tothe optimization of the automatic supply of the machining liquid.

Comparison of the present invention with the above-mentioned four priorart will be described below. The first prior art is so configured thatthe position of the machining liquid nozzle can be adjusted only in adirection along the diameter, i.e. radially of the tool (grindingwheel). The second and third prior art are so configured that theposition of the machining liquid supply nozzle can be adjusted only in acircumferential direction, i.e. in a direction tangential to the tool(grinding wheel) at the machining point. According to the presentinvention, in contrast, the position of the machining liquid nozzle canbe adjusted in both radial and circumferential directions of the tool,and therefore the machining liquid can be supplied from the optimalposition in response to the change in the tool diameter or the machiningpoint. Further, the fourth prior art is so configured that the positionof the machining liquid nozzle can be adjusted in both the radial andcircumferential directions of the tool, but the adjustment of thecircumferential position is limited. In contrast, the present inventionis free of such a limitation of the position of adjusting the machiningliquid nozzle in the circumferential direction of the tool, andconfigured so that the position adjustment is possible over the entirecircumference of the tool. Therefore, the machining liquid can besupplied properly without any dead angle.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be further explained below in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a perspective view showing a configuration of an essentialpart of a machine tool system constituting a grinding machine having amachining liquid supply device for supplying a machining liquid to aportion ground by a grinding wheel according to an embodiment of thepresent invention;

FIG. 2 is a partial front view showing the relation between a machiningliquid supply nozzle of the machining liquid supply device and theportion of the workpiece grinded by the grinding wheel, and thepositional relation between the grinding wheel and a tool reconditioningmeans for truing or dressing a tool such as the grinding wheel as viewedfrom the front side of a spindle of the grinding machine shown in FIG.1;

FIG. 3 is a perspective of an essential part, showing cylindricalsupporting means arranged on an area surrounding the circumference ofthe spindle rotatable within the spindle head of the grinding machine,the cylindrical supporting means being adapted to support the machiningliquid supply device having a machining liquid supply nozzle movably intwo directions, i.e., in circumferential and radial directions, bylinear movement means and rotating movement means;

FIG. 4 is a perspective sectional view of an essential part, showing anengagement between a worm and a worm wheel making up the rotatingmovement means and the linear movement means and an engagement between arack and a pinion, thereby to allow the machining liquid supply deviceto be moved in the circumferential direction and radial direction,respectively;

FIG. 5 is a perspective view of an essential part, showing cylindricalsupporting means arranged on an area surrounding the circumference ofthe spindle rotatable within the spindle head of the grinding machine,the cylindrical supporting means being adapted to support the machiningliquid supply device having a machining liquid supply nozzle movably intwo directions, i.e., in circumferential and radial directions, byturning movement means and rotating movement means;

FIG. 6 is a front view showing a configuration of a grinding machineaccording to an embodiment of the present invention, which includes aspindle head having a spindle with a grinding wheel mounted thereon anda bed with a workpiece and a tool measuring means mounted thereon; and

FIG. 7 is a side view showing an arrangement of tool measuring means anda workpiece-mounting rotary head mounted on the bed of FIG. 6 through arotary head base.

BEST MODE FOR CARRYING OUT THE INVENTION

First, referring to FIGS. 1 and 2, a machine tool MT is shown as agrinding machine according to an embodiment thereof. The machine tool MThas a spindle head 10, and a spindle 12 is supported for high speedrotation in the spindle head 10. A grinding wheel or tool, i.e., anexample of a tool T, is mounted on a tool mount 12 a of the spindle 12.The spindle head 10 is mounted on a machine column 14 so that it can bemoved relative to the bed, not shown, together with the machine column14 or can be moved relative to the machine column 14, in directionsparallel to two orthogonal axes (i.e., X- and Y-axes) as shown. Therespective movements of the spindle head 10 and the spindle 12 supportedby the spindle head 10 in directions parallel to those two orthogonalaxes are detected by position detectors (not shown), such as scales,arranged on the machine tool; and associated with those two axes,respectively.

Also, the machine tool MT, i.e., the grinding machine according to thisembodiment thereof, is provided with a tool reconditioning unit Dcapable of performing the tool reconditioning process, while thegrinding process is going on, by truing or dressing the grinding wheelor tool mounted on the spindle 12 through the tool mount 12 a. A dressertool DT is mounted on the foremost portion of the tool adjusting unit D.

The machine tool MT is further provided with a cylindrical supportingbody 16 arranged rotatably by means of a bearing unit described later inan area surrounding the spindle head 10. The machining liquid supplydevice 18 is carried on the cylindrical supporting body 16 so as to berotatable about the center axis of spindle head 10, i.e. about therotational center axis of the spindle 12, along with the rotation of thecylindrical supporting body 16.

This machining liquid supply device 18 is provided with a machiningliquid receiving unit 18 a connected to a machining liquid source (notshown), a piping unit 18 b and a machining liquid supply nozzle 20mounted at the forward end 18 c of the piping unit 18 b through anappropriate rotatable connector 18 d (see FIG. 2). The machining liquidis discharged and supplied from an opening end of the machining liquidsupply nozzle 20 toward the machining portion between the tool T and theworkpiece W (see FIG. 2), i.e. toward the contact area P between thegrinding wheel T and the workpiece W.

The contact area P between the grinding wheel T and the workpiece W isdisplaced every moment with the progress of the grinding process and theabrasion of the grinding wheel T. Both of a rotating movement mechanism(rotating movement means) and a linear movement mechanism (linearmovement means) for setting a position and a orientation of themachining liquid supply nozzle 20 moves the machining liquid supplynozzle 20 via the cylindrical supporting body 16 to always direct theopening end of the machining liquid supply nozzle 20 of the machiningliquid supply device 18 of the machine tool MT toward the contact areaP, under the optimum conditions for supplying the machining liquid, i.e.in such a manner as to follow the displacement of the contact area Pduring the progress of the grinding process on the workpiece W. Now,these two mechanisms will be explained with reference to FIGS. 1 and 2as well as to FIGS. 3 and 4.

The cylindrical supporting body 16 for carrying the machining liquidsupply device 18 is mounted around the spindle head 10 by means ofrotary bearings 22 a, 22 b (see FIG. 4) such as well-known ball bearingsor the like in such a manner as to be rotatable through 360° about theaxis of the spindle head 10 and the spindle 12 as described above, i.e.over the entire circumference of the spindle head 10 and the spindle 12.Along with the rotation of the cylindrical supporting body 16,therefore, the machining liquid supply device 18 can be also rotatedthrough 360° over the entire circumference about the axis of the spindlehead 10 and the spindle 12.

On the other hand, a linear guide portion 16 a is formed as an L-shapedoutward protrusion in the radial direction on a part of the front edgeof the cylindrical supporting body 16. The machining liquid supplydevice 18 is integrally coupled with a linear rod 17 fitted linearlyslidably into a linear guide groove 16 formed in a guide block 16 b of alinear guide portion 16 a, thereby allowing the machining liquid supplydevice 18 to be linearly movable. The linear movement of the machiningliquid supply device 18 is designed and preset to move themachining.liquid supply nozzle 20 in radial direction toward and awayfrom the axis of the spindle 12. As a result, the opening end of themachining liquid supply nozzle 20 shown in FIG. 1 is movable in radialdirection toward and away from the rotational axis of the grinding wheelT mounted on the spindle 12.

The first worm wheel 32 of the cylindrical supporting body 16 making upthe rotating movement mechanism 30 is fixedly attached, by appropriatefixing means, on the side of the rear edge axially spaced from the sideof the front edge having the linear guide portion 16 a of thecylindrical supporting member 16. The first worm 34 is in mesh with thefirst worm wheel 32. By rotationally driving the first worm 34, therotating force is applied to the first worm wheel 32, with the resultthat the cylindrical supporting body 16 is rotatable through 360° aboutthe axis of the spindle head 10 and the spindle 12 by means of therotary bearings 22 a, 22 b. In the process, the shaft 36 of the firstworm 34 is rotatably held by means of an appropriate rotary bearingbetween a pair of rotation holding portions 38 a, 38 b located on abracket 38 mounted on the spindle head 10, as clearly shown in FIG. 3. Apulley 36 a is mounted at an end of the shaft 36 of the first worm 34,while a driving motor 40 such as a servo motor is held on the bracket38. A pulley 42 a is mounted at the forward end of the output shaft 40 aof the driving motor 40. The pulley 42 a on the side of the drivingmotor 40 and the pulley 36 a on the side of the first worm 34 areconnected by a well-known timing belt 44, so that the first worm 34 isrotated by the rotating force of the driving motor 40.

Specifically, the rotating movement mechanism 30 for rotationally movingthe machining liquid supply nozzle 20 of the machining liquid supplydevice 18 via the cylindrical supporting body 16 includes abelt-and-pulley mechanism having the driving motor 40, the timing belt44 and the pulleys 36 a, 42 a, the first worm 34 and the first wormwheel 32. In this way, by controlling the rotation of the driving motor40 and the driving motor 50 synchronously, the amount of rotatingmovement of the cylindrical supporting body 16 about the axis of thespindle can be controlled over the entire circumference to locate andset the supporting body 16 in a desired circumferential position.

A cylindrical gear carrier 50 is located at an intermediate portionbetween the front and rear ends of the cylindrical supporting body 16 soas to be rotatable about the axis of the spindle head 10 and the spindle12 with respect to them by means of ball bearings 52 a, 52 b. A secondworm wheel 54 is fixedly attached in parallel to the first worm wheel 32on the outer periphery of the gear carrier 50. In other words, thesecond worm wheel 54 is mounted on the gear carrier 50 to be rotatabletogether with the gear carrier 50. A pinion 56 is also fixedly attachedon the gear carrier 50 in parallel to the second worm wheel 54. Rackteeth 58 formed on an inner surface of a rack 60 are in mesh with thepinion 56 as clearly shown in FIG. 4. At the same time, the rack 60 iscoupled to the linear rod 17 described above by appropriate fixing meanssuch as a bolt and therefore integrated with the machining liquid supplydevice 18. Thus, the rotation of the gear carrier 50 linearly moves therack 60 in a longitudinal direction thereof because of the mesh of therack 60 with the pinion 56. As a result, the machining liquid supplydevice 18 integrated with the rack 60 via the linear rod 17 is movedlinearly, so that the machining liquid supply nozzle 20 linearly movesin radial direction of the spindle head 10 and the spindle 12 withrespect to their center axes. A second worm 66 is in mesh with thesecond worm wheel 54, as is clearly shown in FIG. 3. The second worm 66has a shaft 68 and is rotatably mounted, by means of a rotary bearing(not shown), to a pair of holders 72 a, 72 b located on the bracket 70mounted on the spindle head 10. A pulley 74 is fixedly attached at oneend of the shaft 68 of the second worm 66, while a pulley 78 a ismounted at the forward end of the output shaft 76 a of the driving.motor76 such as a servo motor held on the bracket 70. A timing belt 78 b isput in tension between the pulley 78 a and the pulley 74 of the secondworm 66. As a result, by controlling the rotation of the driving motor76, the machining liquid nozzle 20 of the machining liquid supply device18 is driven in a radial direction of the spindle head 10 and thespindle 12 with respect to their center axes, as described above, by thebelt-and-pulley mechanism including the timing belt 78 b and the pulleys74, 78 a and by the linear movement mechanism 80 including the secondworm 66, the second worm wheel 54, the pinion 56 and the rack 60. In theprocess, it is necessary to stop the driving motor 40 rotating the firstworm wheel 32 in order to lock the cylindrical supporting body 16. It isof course possible to reverse the rotational direction of the secondworm wheel 54 and the pinion 56 so that the machining liquid nozzle 20moves toward or away from the center axis of the cylindrical supportingbody 6 in radial direction.

For moving the machining liquid supply nozzle 20 linearly toward or awayfrom the center axis of the spindle 12, the length of the rack 60, thesize and the number of the rack teeth 58 and the teeth of the pinion 56may be appropriately selected and designed in accordance with a requiredmaximum range and minimum unit of linear movement depending on a maximumvalue of a diameter T of a grinding wheel to be used. The pinion 56 maybe also formed as a partial gear, as required.

Both of the rotating movement mechanism 30 and the linear movementmechanism 80 for moving the machining liquid supply nozzle 20 of themachining liquid supply device 18 rotationally and linearly,respectively, are adapted to carry the driving motors 40, 76 on thebrackets 38, 70 located in the outer peripheral area surrounding thecircumference of the spindle head 10 having the cylindrical supportingbody 16 mounted rotatably thereon, while at the same time being adaptedto drive to rotate, by means of the relatively smaller first and secondworms 34, 66, the cylindrical supporting body 16 and the first andsecond worm wheels 42, 54 mounted thereon. Therefore, the rotation ofthe cylindrical supporting body 16 is not mechanically interfered withby any members or mechanical parts. As a result, this allows themachining liquid supply device 18 and the machining liquid supply nozzle20 to be rotated through 360° over the entire circumference about theaxis of the spindle 12. Further, in combination with the linear movementof the liquid supply device 18 in the radial direction, the opening endof the machining liquid supply nozzle 20 can be positioned and set in anoptimum position and orientation for supplying the machining liquid tothe contact area P between the grinding wheel T and the workpiece W.

An embodiment different from the aforementioned embodiment will beexplained with reference to FIG. 5. Reference numerals similar to thoseof the embodiment shown in FIGS. 1 to 4 described above will not beexplained.

The embodiment shown in FIG. 5 and the embodiment shown in FIGS. 1 to 4are different in the provision of a turning movement mechanism 120instead of the linear movement mechanism 80. The turning movementmechanism 120 is adapted to carry a driving motor 122 by the bracket 70located in the outer peripheral area surrounding the spindle head 10having the cylindrical supporting body 16 rotatably mounted thereon, andto drive to rotate a third worm wheel 126 mounted on the cylindricalsupporting body 16, via the third worm 124. The driving force of thedriving motor 122 is transmitted to the third worm 124, as in the linearmovement mechanism 80, by a belt-and-pulley mechanism. A pinion 126 isintegrated with the third worm wheel 125 and is in mesh with a pinion128. A shaft portion 130 having the machining liquid supply nozzle 20 atthe forward end or the tip thereof is integrated with the pinion 128 andis rotatably supported by means of a well-known bearing or the likeinside the machining liquid supply device 18. Specifically, the shaft130 having the machining liquid supply nozzle 120 is adapted to turnabout the axis thereof through the third worm 124, the third worm wheel125, the pinion 126 and the pinion 128, by driving the driving motor122.

According to this embodiment, a combination of the turning movement bythe turning movement mechanism 120 and the rotating movement by therotating movement mechanism 30 achieve the positioning of the machiningliquid supply nozzle 20 with respect to the contact area P between thegrinding tool T and the workpiece W. The difference of this embodimentfrom the aforementioned one is that the machining liquid supply nozzle20 is positioned in the radial direction of the grinding tool T by theturning movement mechanism 120. Specifically, the synchronous operationof the rotating movement mechanism 30 and the turning movement mechanism120 makes it possible to position the machining liquid supply nozzle 20with respect to the contact area P between the grinding tool T and theworkpiece W.

The positioning of the machining liquid supply nozzle 20 incircumferential direction of the grinding tool T by the rotatingoperation of the rotating movement mechanism 30 and the positioning ofthe machining liquid supply nozzle 20 in the radial direction of thegrinding tool T by the turning operation of the turning movementmechanism 120 can be performed separately from each other. Also, thesequence of the operations is not specifically limited. Even theprovision of the turning movement mechanism 120 still allows themachining liquid supply nozzle 20 to be rotated through 360° over theentire periphery of the spindle 12 about the axis of the spindle 12without any interference, as in the embodiment described above.

In the case where the workpiece W is ground with the machining liquidsupplied from the machining liquid supply device 18 of the machine tool(grinding machine) MT, the surface grinding of the workpiece W can beperformed with the machining liquid supplied thereto under substantiallythe optimum condition, if the spindle head 10 is adapted to be movablein the directions along two orthogonal axes with respect to the column14 and provided is a work table (not shown) which can move the workpieceW in the direction of Z-axis, i.e., the direction of the other one axisorthogonal to the aforementioned two orthogonal directions (X- andY-axes) in a plane, so that the workpiece W placed on this work table isground using the grinding wheel T.

On the other hand, another embodiment of a machine tool MT is shown inFIGS. 6 and 7, in which a work table capable of moving the workpiece Wonly in one direction along Z-axis is replaced by a rotary table notonly capable of feeding the workpiece W placed thereon along Z-axis in aplane but also capable of rotating the workpiece W about, for example, ahorizontal axis, and in which the workpiece W is mounted on this rotarytable and the grinding wheel T of variously different diameters storedin a tool storage means are selectively changed and mounted on thespindle 12 thereby to carry out the desired grinding process. In thisembodiment, the same component elements as those of the machine toolshown in FIGS. 1 to 5 are designated by the same reference numerals,respectively.

Referring to FIGS. 6 and 7, the machine tool MT is provided with a toolstorage unit 90 such as a well-known tool magazine and the like, asdescribed later. Either one of the tools (grinding wheels) T stored inthe tool storage unit 90 or a work measuring device M_(R) capable ofmeasuring the external dimensions and the shape of a workpiece by directcontact can be detachably mounted on the spindle 12 supported in thespindle head 10 by a tool changing means (not shown) such as awell-known tool changing arm. The continuous lines in the upper part ofFIG. 6 show a state in which a grinding wheel T, i.e., an example of atool T, taken out from the tool storage unit 90 is mounted on thespindle 12 by the tool changing means, while the broken lines in thelower part of FIG. 6 show a state in which the work measuring deviceM_(R) is, mounted on the spindle 12.

On the other hand, a table 94 is mounted on the bed 92 opposite to thespindle head 10 so as to be movable in one direction (along Z-axis)orthogonal to the aforementioned directions along the two axes. A rotaryhead 98 is mounted on the table 94 through a rotary head base 96. Theworkpiece W to be machined is gripped by a work gripping device 100rotatable for indexing and held in a central portion of the rotary head98. The work gripping device 100 can be turned for indexing by a drivingmotor (not shown) such as a servo motor encased in the rotary head 98.

The machine tool MT is connected to a machine control unit 102. Inaccordance with an instruction from the machine control unit 102, themachining liquid supply device 18 described above is set in position andorientation, and otherwise the operation of all the movable parts of themachine can be controlled.

Also, an automatic tool measuring device 110 is located at apredetermined position on the table 94. Specifically, the automatic toolmeasuring device 110 is disposed at a predetermined reference positionwith respect to X-, Y- and Z-axes on the table 94, and the referenceposition data (coordinates on a coordinate system defined by X-, Y- andZ-axes) is known as reference position data in advance. As shown in FIG.7, the automatic tool measuring device 110 can be stored inside thetable 94 to avoid damage and then covered with a lid 112. The automatictool measuring device 110 has, at the forward end thereof, a measuringtip 110 a such as a probe formed of a hard material. The movements ofthe spindle head 10 and the machine column 14 in two directions along X-and Y-axis directions and the movement of the table 94 along Z-axisbring the tool T (grinding wheel) held on the spindle 12 into contactwith the measuring tip 110 a of the automatic tool measuring device 110thereby to measure the outer diameter of the grinding wheel T.Specifically, the reference position data on the reference position ofthe measuring tip 110 a of the automatic tool measuring device 110 withrespect to the bed 92 in the directions along X-, Y- and Z-axes arestored beforehand as known data in the machine control unit 102. Thus,by supplying the machine control unit 102 with the position data of themeasuring tip 110 a with respect to X-, Y- and Z-axes input from theposition detector on the machine at the time when the grinding wheel Tcomes into contact with the measuring tip 110 a, the actual measurementof the outer diameter of the grinding wheel T can be determined bycalculations.

Also in the case where the work measuring device M_(R) is mounted on thespindle 12 as described above, the position of the center of the spindle12 is stored in the machine control unit 102 as known data. Thus, whenthe spindle 12 and the table 94 relatively approach each other in thedirections along the three axes (X-, Y- and Z-axes) and thereby themeasuring tip of the work measuring device M_(R) comes into contact withthe outer surface of the workpiece W mounted in the work gripping device100, the external dimensions of the workpiece W can be determined bysimple arithmetic operations in the machine control unit 102 from themeasured movement of the spindle 12 and the known data on the referenceposition of the spindle 12. In the process, the automatic tool measuringdevice 110 can of course be a non-contact measuring device capable ofmeasuring the dimensions of the workpiece without touching the workpieceW.

In the machine tool according to this embodiment of the presentinvention, the machining liquid supply device 18 and the toolreconditioning unit D for truing or dressing the tool are installedconstantly in the area surrounding the circumference the spindle head 10provided with the spindle 12. This machining liquid supply device 18, asdescribed with reference to the foregoing embodiments, has an openingend of the machining liquid supply nozzle 20, and is connected by pipingto a machining liquid source such as a machining liquid tank and.thelike, not shown in FIGS. 6 and 7. The machining liquid supply nozzle 20is arranged in such a manner that when the workpiece W is ground by thegrinding wheel T, the chips produced in a machining area are rapidlyflushed away by spouting the machining liquid through the opening end atthe forward end of the nozzle 20 to the contact area P where thegrinding wheel T and the workpiece T engage with each other to machinethe workpiece W, while at the same time cooling both the grinding wheelT and the workpiece W to ensure proper and smooth machining.

What is claimed is:
 1. A machine tool system for machining a workpieceby moving a tool mounted on a spindle and the workpiece mounted on atable included in the machine tool system relative to each other inthree directions along an X-axis, a Y-axis and Z-axis, said machine toolsystem comprising: a spindle head for rotatably supporting the spindle;a column for movably supporting the spindle head; a tool mounting meansfor detachably mounting the tool on the spindle; a machining liquidsupply means including a machining liquid nozzle for spouting amachining liquid toward a machining area where the tool engages with theworkpiece, and connected by piping to a machining liquid source; acylindrical supporting means disposed in an area surrounding thecircumference of the spindle for movably supporting the machining liquidnozzle of the machining liquid supply means; a radial moving means forpositioning, in a radial direction of the tool, the machining liquidnozzle of the machining liquid supply means supported on the cylindricalsupporting means, by linearly moving or turning the machining liquidnozzle with respect to the tool; and a circumferential moving means forpositioning the machining liquid nozzle of the machining liquid supplymeans over the entire circumference of the tool by rotating thecylindrical supporting means.
 2. The machine tool system according toclaim 1, wherein the radial moving means comprises a rack located on themachining liquid nozzle of the machining liquid supply means, a pinionmovable relative to the cylindrical supporting means and in mesh withthe rack, a worm wheel movable relative to the cylindrical supportingmeans together with the pinion, a worm in mesh with the worm wheel, anda linear movement motor fixed on the column for driving to rotate theworm.
 3. The machine tool system according to claim 1, wherein theradial moving means comprises a pinion located on the machining liquidnozzle of the machining liquid supply means, a worm wheel having apinion in mesh with the pinion and being movable relative to thecylindrical supporting means, a worm in mesh with the worm wheel, and aturning movement motor fixed on the column for driving to rotate theworm.
 4. The machine tool system according to claim 1, wherein thecircumferential moving means comprises a worm wheel integrated with thecylindrical supporting means, a worm in mesh with the worm wheel, and arotating movement motor fixed on the column for driving to rotate theworm.
 5. The machine tool system according to claim 1, furthercomprising a rotary table having at least one rotational feed shaft anda work rotating means for rotationally feeding the workpiece mounted onthe rotary table.
 6. The machine tool system according to claim 1,wherein the tool mounted on the spindle comprises a grinding wheel. 7.The machine tool system according to claim 6, further comprising a toolmeasuring means located in a part of a structure of the machine toolsystem for measuring a diameter or a tip position of the grinding wheelmounted on the spindle.
 8. The machine tool system according to claim 6,further comprising a tool reconditioning means located on the column fortruing or dressing an outer peripheral portion of the grinding wheelmounted on the spindle.
 9. A machining liquid supply device of a machinetool system for supplying a machining liquid to a machining area where atool mounted on a spindle engages with a workpiece mounted on a tableincluded in the machine tool system, said machining liquid supply devicecomprising: a machining liquid supply means including a machining liquidnozzle for spouting the machining liquid toward the machining area andconnected by piping to a machining liquid source; a cylindricalsupporting means disposed in an area surrounding the circumference ofthe spindle for movably supporting the machining liquid nozzle of themachining liquid supply means; a radial moving means for positioning, ina radial direction of the tool, the machining liquid nozzle of themachining liquid supply means supported on the cylindrical supportingmeans, by linearly moving or turning the machining liquid nozzle withrespect to the tool; and a circumferential moving means for positioningthe machining liquid nozzle of the machining liquid supply means overthe entire circumference of the tool by rotating the cylindricalsupporting means.
 10. The machining liquid supply device of a machinetool system according to claim 9, wherein the radial moving meanscomprises a rack located on the machining liquid nozzle of the machiningliquid supply means, a pinion movable relative to the cylindricalsupporting means and in mesh with the rack, a worm wheel movablerelative to the cylindrical supporting means together with the pinion, aworm in mesh with the worm wheel, and a linear movement motor fixed on apart of structure of the machine tool system for driving to rotate theworm.
 11. The machining liquid supply device of a machine tool systemaccording to claim 9, wherein the radial moving means comprises a pinionlocated on the machining liquid nozzle of the machining liquid supplymeans, a worm wheel having a pinion in mesh with the pinion and beingmovable relative to the cylindrical supporting means, a worm in meshwith the worm wheel, and a turning movement motor fixed on a part of astructure of the machine tool system for driving to rotate the worm. 12.The machining liquid supply device of a machine tool system according toclaim 9, wherein the circumferential moving means comprises a worm wheelintegrated with the cylindrical supporting means, a worm in mesh withthe worm wheel, and a rotating movement motor fixed on a part of astructure of the machine tool system for driving to rotate the worm.